Article coated with aromatic sulfonamide intumescent agent

ABSTRACT

Coated articles of the invention are substrates coated with intumescent compositions which comprise certain aromatic sulfonamides bearing a nuclear substituent which is linked to the aromatic ring through a nitrogen atom. Exemplary of the intumescent agents are p-aminobenzenesulfonamide, pacetamidobenzenesulfonamide, and the corresponding naphthalenesulfonamides.

.. ed States Patent [1 1 Roth et a1.

[ ARTICLE COATED WITH AROMATIC SULFONAMIDE INTUMESCENT AGENT [76] Inventors: Shirley ll. Roth, Highland Park;

Joseph Green, East Brunswick, both of NJ.

[22] Filed: Dec. 23, 1971 [211 App]. No.: 211,636

[52] US. Cl. 117/136, 106/15 FP, 252/8.1 [51] Int. Cl 844d l/44 [58] Field of Search 117/136; 252/8.l;

106/15 FP; 260/556 B, 397.7

[56] References Cited UNITED STATES PATENTS 10/1966 Pettigrew 260/556 B 9/1944 McNally et a1 260/556 B 11/1971 Bujwid 260l397.7

[ Oct. 30, 1973 5/1972 Sawko 117/136 10/1970 Webb 117/136 Primary ExaminerWilliam D. Martin Assistant Examiner-Janyce A. Bell Att0rneyRichard S. Strickler, Elton F. Gunn, Burton E. Levin, Joshua J. Ward, Edwin T. Yates, George L. Rushton, A. Joe Reinert and Patricia J. Hogan [5 7] ABSTRACT 7 Claims, No Drawings ARTICLE COATED WITH AROMATIC SULFONAMIDE INTUMESCENT AGENT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to intumescent compositions and more particularly relates to such compositions containing a one-component intumescent agent.

2. Description of the Prior Art It is known that a substrate may be protected from heat and fire by the application of an intumescent composition. lntumescent compositions of the prior art ususally contain an intumescent agent having at least three components, i.e., a carbonific, a spumific, and a catalyst; and they are typically characterized by the disadvantages of high cost, low spreading rate, relatively poor efficiency, poor water resistance, and poor weatherability.

As disclosed in US. Pat. No. 3,535,130, it has already been discovered that a one-component intumescent agent has advantages over multicomponent intumescent agents. However, the intumescent agents of the patent have poor adherence to substrates and have an undesirable degree of moisture sensitivity.

SUMMARY OF THE INVENTION An object of this invention is to provide a novel class of one-component intumescent agents.

Another object is to provide such intumescent agents having good efficiency and a low level of moisture sensitivity.

These and other objects are attained by using as intumescent agents compounds corresponding to the formula:

wherein Ar is a divalent aromatic residue and R is hydrogen or a hydrocarbon, halohydrocarbon, or acyl radical.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The intumescent agents of the invention may be any compounds corresponding to the above formula. However, they are preferably compounds wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof. When the aromatic ring bears organic substituents, it is usually preferred that these substituents contain one to five carbon atoms. When there are halo substituents, it is usually preferred that they be chloro or bromo. It is also preferred that the aromatic ring have at least one free reactive position.

As indicated above, R of the formula may be hydrogen or a hydrocarbon, halohydrocarbon, or acyl radical, e.g., an alkyl, chloroalkyl, or bromoalkyl radical containing one to five carbon atoms, a phenyl, chloro phenyl, or bromophenyl radical, or an aliphatic or aromatic acyl radical.

Exemplary of the intumescent agents of the invention are p-aminobenzenesulfonamide, 2-amino-4- chlorobenzenesulfonamide, 2-amino-4- bromobenzenesulfonamide, 4-amino-2-ethylbenzenesulfonamide, 3-amino-4-chloromethylbenzenesulfonamide, 4-amino-2-butoxybenzenesulfonamide, 4- amino-3-chloromethoxybenzenesulfonamide, 4-amino- 3-carboxybenzenesulfonamide, 3 ,4- diaminobenzenesulfonamide, 4-amino-2- acetamidobenzenesulfonamide, 2-amino-4- nitrobenzenesulfonamide, 4- methylaminobenzenesulfonamide, 4-chloroethylaminobenzenesulfonamide, 2-bromoethylaminobenzenesulfonamide, 4- phenylaminobenzenesulfonamide, 4-( pchlorophenylamino)benzenesulfonamide, 4-( p- (bromophenylamino )benzenesulfonamide, p-

acetamidobenzenesulfonamide, p-benzamidobenzenesulfonamide, the corresponding naphthalenesulfonamides, etc. The preferred intumescent agents include p-aminobenzenesulfonamide and pacetamidobenzenesulfonamide. When not readily available, these compounds may be prepared by known techniques.

For use in protecting a substrate from heat and fire, the intumescent agents of the invention may be applied in any suitable manner, e.g., electrodeposition, spraying of powdered intumescent agent onto an adhesive substrate, etc. However, it is usually preferred to compound the intumescent agent with a binder, e.g., nitrocellulose, and optionally also with one or more of the other ingredients conventionally used in intumescent compositions, e.g., stabilizers, dispersing agents, pigments, driers, biocides, anti-foamers, thickeners, protective colloids, tillers, blowing agents, etc.; disperse the composition in a suitable liquid medium, e.g., water or a solvent or solvent mixture; and apply the coating composition thus formed to the substrate to be protected. As is the case with conventional intumescent coating compositions, it is frequently convenient to apply these coating compositions in the form of a paint having a solids content of about 10-70 percent by weight and an intumescent agent/binder weight ratio of about 0.075-14/1 to deposit a coating having a dry thickness of about 0.001-0.75 inch.

The intumescent agents of the invention are efficient, have low moisture sensitivity, and intumesce to form foams having good volume, cell structure, and adherence to substrates, such as wood, metal, and plastics. They are also useful as flame retardants in normally flammable compositions.

The following examples are given to illustrate the invention and are not intended as a limitation thereof. Unless otherwise specified, parts mentioned are parts by weight.

EXAMPLE I Place 1 gram of p-acetamidobenzenesulfonamide in an aluminum pan and flame it with a propane torch. The compound intumesces to form an excellent volume of foam having a good cell structure.

EXAMPLE II Ball mill a mixture of 84 parts of paminobenzenesulfonamide, 27 parts of a vinyl chloride/vinylidene chloride copolymer, 6 parts of titanium dioxide, and parts of methyl ethyl ketone to form a coating composition. Apply the composition to four poplar test panels to form films having a dry thickness of 0.024 inch. Test the panels in accordance with the two-foot tunnel test described in H. L. Vandersall, The Use of a Small Flame Tunnel for Evaluating Fire Hazard, JOURNAL OF PAINT TECHNOLOGY, Vol. 39, N0. 511, pp. 494-500 (1967). The panels have an average flame spread rating of 24 and an average degree of intumescence of 5 mm.

EXAMPLE llI wherein Ar is a divalent aromatic residue and R is hydrogen or a hydrocarbon, halohydrocarbon, or acyl radical.

2. The article of claim 1 wherein Ar is a divalent aro matic residue derived from benzene or naphthalene or an alkyl. haloalkyl. alkoxy, haloalkoxy. halo, hydroxy, carboxy, amino. amido. or nitro derivative thereof.

3. The article of claim 2 wherein Ar is a divalent aromatic residue derived from benzene.

4. The article of claim 1 wherein R is hydrogen.

5. The article of claim 1 wherein R is an aliphatic acyl radical containing one to five carbon atoms.

6. The article of claim 1 wherein the intumescent agent is p-aminobenzenesulfonamide.

7. The article of claim 1 wherein the intumescent agent is p-acetamidobenzenesulfonamide.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3.769.078 I Dated October 30, 1973 Inventor(s) ShirIey H. Roth, 8t 8.].-

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Cover page, between items [76] and [22], insert [73] Assignee: Cities Service Company, New York, N, Y.

Signed and sealed this 2nd day of April 19724..

(SEAL) Attest:

EDWARD M.FLETCHER, JR c MARSHALL DANN Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5759.078 I Dated October 30, I973 Invent r( Shirley H. ROth, at al.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Cover page, between items [76] and [22], insert [73] Assignee: Cities Service Company, New York, N Y.

Signed and sealed this 2nd day of April 1971+.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents 

2. The article of claim 1 wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof.
 3. The article of claim 2 wherein Ar is a divalent aromatic residue derived from benzene.
 4. The article of claim 1 wherein R is hydrogen.
 5. The article of claim 1 wherein R is an aliphatic acyl radical containing one to five carbon atoms.
 6. The article of claim 1 wherein the intumescent agent is p-aminobenzenesulfonamide.
 7. The article of claim 1 wherein the intumescent agent is p-acetamidobenzenesulfonamide. 